diff options
Diffstat (limited to 'doc/supplements/m68k/cpumodel.t')
| -rw-r--r-- | doc/supplements/m68k/cpumodel.t | 91 |
1 files changed, 0 insertions, 91 deletions
diff --git a/doc/supplements/m68k/cpumodel.t b/doc/supplements/m68k/cpumodel.t deleted file mode 100644 index d9bf601e1f..0000000000 --- a/doc/supplements/m68k/cpumodel.t +++ /dev/null @@ -1,91 +0,0 @@ -@c -@c COPYRIGHT (c) 1988-1998. -@c On-Line Applications Research Corporation (OAR). -@c All rights reserved. -@c -@c $Id$ -@c - -@chapter CPU Model Dependent Features - -@section Introduction - -Microprocessors are generally classified into -families with a variety of CPU models or implementations within -that family. Within a processor family, there is a high level -of binary compatibility. This family may be based on either an -architectural specification or on maintaining compatibility with -a popular processor. Recent microprocessor families such as the -SPARC or PA-RISC are based on an architectural specification -which is independent or any particular CPU model or -implementation. Older families such as the M68xxx and the iX86 -evolved as the manufacturer strived to produce higher -performance processor models which maintained binary -compatibility with older models. - -RTEMS takes advantage of the similarity of the -various models within a CPU family. Although the models do vary -in significant ways, the high level of compatibility makes it -possible to share the bulk of the CPU dependent executive code -across the entire family. Each processor family supported by -RTEMS has a list of features which vary between CPU models -within a family. For example, the most common model dependent -feature regardless of CPU family is the presence or absence of a -floating point unit or coprocessor. When defining the list of -features present on a particular CPU model, one simply notes -that floating point hardware is or is not present and defines a -single constant appropriately. Conditional compilation is -utilized to include the appropriate source code for this CPU -model's feature set. It is important to note that this means -that RTEMS is thus compiled using the appropriate feature set -and compilation flags optimal for this CPU model used. The -alternative would be to generate a binary which would execute on -all family members using only the features which were always -present. - -This chapter presents the set of features which vary -across SPARC implementations and are of importance to RTEMS. -The set of CPU model feature macros are defined in the file -c/src/exec/score/cpu/m68k/m68k.h based upon the particular CPU -model defined on the compilation command line. - -@section CPU Model Name - -The macro CPU_MODEL_NAME is a string which designates -the name of this CPU model. For example, for the MC68020 -processor, this macro is set to the string "mc68020". - -@section Floating Point Unit - -The macro M68K_HAS_FPU is set to 1 to indicate that -this CPU model has a hardware floating point unit and 0 -otherwise. It does not matter whether the hardware floating -point support is incorporated on-chip or is an external -coprocessor. - -@section BFFFO Instruction - -The macro M68K_HAS_BFFFO is set to 1 to indicate that -this CPU model has the bfffo instruction. - -@section Vector Base Register - -The macro M68K_HAS_VBR is set to 1 to indicate that -this CPU model has a vector base register (vbr). - -@section Separate Stacks - -The macro M68K_HAS_SEPARATE_STACKS is set to 1 to -indicate that this CPU model has separate interrupt, user, and -supervisor mode stacks. - -@section Pre-Indexing Address Mode - -The macro M68K_HAS_PREINDEXING is set to 1 to indicate that -this CPU model has the pre-indexing address mode. - -@section Extend Byte to Long Instruction - -The macro M68K_HAS_EXTB_L is set to 1 to indicate that this CPU model -has the extb.l instruction. This instruction is supposed to be available -in all models based on the cpu32 core as well as mc68020 and up models. |